/**
* j-Interop (Pure Java implementation of DCOM protocol)
*     
* Copyright (c) 2013 Vikram Roopchand
* 
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Vikram Roopchand  - Moving to EPL from LGPL v3.
*  
*/

package org.jinterop.dcom.impls.automation;

import org.jinterop.dcom.common.JIException;


/**<p> Represents the Windows COM <code>IEnumVARIANT</code> Interface. <p>
 *  Sample Usage:- <br>
 *  <code>
 *  //From MSEnumVariant example <br>
 *  JIVariant variant = dispatch.get("_NewEnum"); <br>
 *	IJIComObject object2 = variant.getObjectAsComObject();<br>
 *	IJIEnumVariant enumVARIANT = (IJIEnumVariant)JIObjectFactory.narrowObject(object2.queryInterface(IJIEnumVariant.IID));
 *	<br>
 *	for (i = 0; i < 10; i++) <br>
 *	{ <br>
 *		Object[] values = enumVARIANT.next(1); <br>
 *		JIArray array = (JIArray)values[0]; <br>
 *		Object[] arrayObj = (Object[])array.getArrayInstance(); <br>
 *		for (int j = 0; j < arrayObj.length; j++) <br>
 *		{ <br>
 *			System.out.println(((JIVariant)arrayObj[j]).getObjectAsInt() + "," + ((Integer)values[1]).intValue()); <br>
 *		} <br>
 *	} <br>
 *
 *  </code>
 *
 *  </p>
 * @since 1.0
 *
 */
public interface IJIEnumVariant {

	/**
	 * IID representing the COM <code>IEnumVARIANT</code>.
	 */
	public static final String IID = "00020404-0000-0000-C000-000000000046";

	/** Definition from MSDN: <i>
	 * Attempts to get the next celt items in the enumeration sequence. If fewer than the requested number
	 * of elements remain in the sequence, Next returns only the remaining elements.
	 * </i>
	 *
	 * @param celt number of elements to be returned.
	 * @return results
	 * @throws JIException
	 */
	public Object[] next(int celt) throws JIException;

	/** Definition from MSDN: <i> Attempts to skip over the next celt elements in the enumeration sequence.
	 * </i>
	 *
	 * @param celt number of elements to skip.
	 * @throws JIException
	 */
    public void skip(int celt) throws JIException;

    /**Definition from MSDN:
     * <i>Resets the enumeration sequence to the beginning. There is no guarantee that exactly the same set of
     * variants will be enumerated the second time as was enumerated the first time. Although an exact duplicate
     * is desirable, the outcome depends on the collection being enumerated. You may find that it is impractical
     * for some collections to maintain this condition (for example, an enumeration of the files in a directory).
     * </i>
     * @throws JIException
     */
    public void reset() throws JIException;

    /** Definition from MSDN: <i>
     * Creates a copy of the current state of enumeration. Using this function, a particular point in the enumeration
     * sequence can be recorded, and then returned to at a later time. The returned enumerator is of the same actual
     * interface as the one that is being cloned. <p>
     * There is no guarantee that exactly the same set of variants will be enumerated the second time as was
     * enumerated the first. Although an exact duplicate is desirable, the outcome depends on the collection
     * being enumerated. You may find that it is impractical for some collections to maintain this condition
     * (for example, an enumeration of the files in a directory).
     * </i>
     * @return reference to the clone.
     * @throws JIException
     */
    public IJIEnumVariant Clone() throws JIException;


}
